Studies: Vitamin D deficiency may increase heart risk factors in kids

LOS ANGELES, Aug. 3 (Xinhua) -- Vitamin D deficiency is associated with an increased incidence of risk factors for cardiovascular problems such as heart attack and stroke in kids, two new studies find.

The two studies, published in the Aug. 3 online edition of Pediatrics, used U.S. data from the 2001-2004 National Health and Nutrition Examination Survey.

There was a clear association with cardiovascular risk factors. The 25 percent of youngsters with the lowest levels of vitamin D were 2.36 times more likely to have high blood pressure, 54 percent more likely to have low HDL cholesterol levels, 2.54 times more likely to have elevated blood sugar levels and 3.88 times more likely to have metabolic syndrome, a constellation of risk factors including obesity, high blood fats and high blood pressure, the two studies show.

While previous studies have linked vitamin D deficiency to increased risk in American adults, "few studies have looked at whether vitamin D can be associated with increased cardiovascular disease in children," said Jared P. Reis, who began his study while at Johns Hopkins University. He is now an epidemiologist in the division of cardiovascular sciences of the U.S. National Heart, Lung, and Blood Institute.

"Nobody questions that vitamin D deficiency causes rickets," said Dr. Michal L. Melamed, an assistant professor of medicine and epidemiology at Albert Einstein College of Medicine in the Bronx, who led the other study. "We wanted to explore other health outcomes and noticed that nobody had described this outcome."

The study she led looked at the overall incidence of low blood levels of vitamin D among young Americans aged one to 21 in the survey. There is no formal definition of vitamin D deficiency, Reis said, but many experts believe that a level of 30 nanograms per milliliter of blood is desirable.